Avid runners, cross-trainers, and the generally health-conscious alike, often take to outdoor running courses or trails as part of a regular cardiovascular fitness training regimen. However, it is overwhelmingly recognized that prolonged periods of excessive running and repetitive high impact strides exerted over concrete or asphalt surfaces, or varied “off-road” terrain, can, and often do, subject the runner to significant joint stress and long-term injury.
More specifically, and as a result of the repetitive joint stress characteristically attributed to the high impact nature of outdoor running, most outdoor runners often develop patellofemoral pain syndrome or “runner's knee,” a slow degradation of the medial, and often lateral, menisci of the knee, causative of a mistracking kneecap. In addition thereto, most such runners are further predisposed to a progressive deterioration of the quadricep muscles, the patellar tendon, and/or cartilaginous structures of the ankle and hip joints.
Accordingly, it has been recommended in fitness and health-related literature that outdoor runners run on grass or other soft ground surfaces so as to reduce overall joint stress. Unfortunately, such “softer” ground surfaces may only fractionally reduce joint stress, and, instead, may present unforeseen dips, bumps and/or generally uneven running surfaces likely to contribute to potentially injurious knee-rotation injuries, ankle sprains or ankle twists.
As such, and in an effort to reduce or avoid joint stress and related injuries, many outdoor runners, and runners in general, utilize treadmills as an equally effective and efficient cardiovascular and/or endurance training means. Specifically, most treadmills incorporate a cushioned deck or suspension system over which a treadmill belt is drawn via motors and associated rollers. Although such cushioned decks or suspension systems are intended to absorb and disperse the shock or impact normally transmitted through and absorbed by the runner's ankle, knee and hip joints, the effective ratio of delivered impact to shock absorption is typically insufficient to stave off the above-discussed effects of repetitive joint stress.
Specifically, the cushioned deck of most mass-commercialized treadmills usually consists of a simple pad or cushion disposed over the top surface or impact-receiving area of the deck. Unfortunately, such pads or cushions are typically short-lived, deteriorate over time as a result of impact and stress, thereby contributing to an uneven running surface and, thus, requiring higher maintenance and/or frequent replacement. Although other less commercially available, and often more expensive, deck-based treadmills incorporating suspension systems and shock absorbers, such as springs, rubber bushings or rubber stabilizers, provide some reduction of impact, deck-based treadmills in general present significant disadvantages that render utilization of same highly impractical, inconvenient and expensive.
That is, most deck-based treadmills, typically comprising a deck manufactured from laminated wood or other suitable material, require the regular application of lubricants over the deck surface to reduce the development of friction and heat thereover during use of the treadmill. Accordingly, failure to regularly apply such lubricants over the deck surface typically results in significant structural and mechanical wear to the deck, and rapid belt deterioration. Additionally, development of excessive friction between the belt undersurface and deck surface may cause drag, pulling and/or intermittent and abrupt cessation of belt movement over the deck following delivery of each impacting stride thereon and thereover; thus, resulting in “amp draw”, a condition in which excessive strain is placed upon the treadmill motor, thereby effectively drawing power away therefrom and eventually “burning-out” or otherwise damaging same. Moreover, most decks require replacement following wear or deterioration of the laminate or wax surfaces—an often burdensome, time—consuming and expensive process.
In an attempt to avoid the maintenance requirements and/or disadvantages of deck-based treadmills, select treadmill manufacturers have developed various deckless treadmill systems. For instance, some such available systems utilize an endless belt guided around two deflection pulleys, wherein the peripheral underside edges of the belt (or the entire underside of the belt) are toothed and adapted to each engage disk-like toothed rims disposed on opposite ends of a smooth-surfaced deflection pulley. Further, a plurality of tread lamellae are secured to the upper surface of the endless belt, wherein a supporting roller arrangement spans the width of the belt so as to provide a supportive understructure proximate the running area or region of the belt. However, upon operation of such a treadmill system, and in conjunction with the forceful impact delivered with each repetitively striking foot of the runner, an exorbitant amount of noise is often generated from the engagement and subsequent release of the toothed surfaces of the belt from the disk-like toothed rims, rendering use of such a system somewhat objectionable. Further, it is apparent that such treadmill systems are not true deckless systems, as the proper operational dependence and structural integrity of such treadmills largely hinges upon such supporting roller arrangements disposed across and proximate to the running area of the belt.
Accordingly, in an effort to provide a more operationally silent treadmill system, other available deckless systems dispose of the toothed-belt/toothed-rim arrangement entirely, and, instead, simply utilize an endless belt guided around two deflection pulleys, wherein the endless belt also comprises tread lamellae secured thereto. Unfortunately, absent any toothed or similarly notched surface, the otherwise smooth surfaces of each deflection pulley may improperly interact with the otherwise smooth undersurface of the treadmill belt; thereby, resulting in significant slip therebetween, and further affecting the maintenance of parallelism between each individual tread lamella due to inter-lamellae tensile and shear forces. Moreover, although such deckless systems may avoid the application of a supporting roller arrangement disposed under the running area of the belt, no effective support mechanism or structure exists for the opposing peripheral edges of the belt portion disposed between the deflective pulleys; thus, contributing to an excessively flexible or overly forgiving and unstable running surface, and injuries commonly associated therewith (i.e., excessive hyperextension of the knee, and ankle twists or sprains).
Other similar treadmill systems, also utilizing an endless-belt guided around two deflection pulleys, further avoid application of a toothed-belt drive arrangement and, instead, incorporate a system of stabilizers to limit or reduce the occurrence of slip between the driven deflection pulley and the belt, and to further maintain parallel alignment of the individual slats or tread lamellae secured to the belt. That is, each tread lamella of such treadmill systems comprises a stem portion that extends through the belt. During operation of the treadmill, and upon approach of the tread lamellae over the driven deflective pulley, each such stem portion is adapted to be engaged by a configuration of narrow, elongated stabilizers connected to and extending from the shaft of the deflection pulley; thereby, reducing slip between the driven deflection pulley and belt, and further assisting in maintaining the tread lamellae in respective parallel orientation. However, in addition to the recognized structural and functional complexities of such treadmills, as well as the impracticalities and difficulties in the manufacture of same, no effective support mechanism is provided for the opposing peripheral edges of the belt portion disposed between the deflective pulleys; thereby, resulting in the afore-mentioned disadvantages.
Still yet a further disadvantage of the above-described treadmill systems is observed with reference to the structural design and construction of the treadmill belts thereof. That is, such prior art treadmill belts are characterized by a multilayer and multi-component construction, typically comprising a lower belt portion over which a plurality of slats or treadmill lamellae are secured via fastening screws or the like. However, in view of the requirement to maintain parallelism of the treadmill lamellae via complex mechanical arrangements of stabilizers as described above, such multilayer constructions further intensify and contribute to the overall structural and design complexities associated with such treadmill systems. Additionally, such multilayer constructions comprise multiple components (i.e., the plurality of slats or treadmill lamellae, fastening screws, bushings, washers, and the like) that inherently require regular and difficult maintenance and/or replacement upon wear.
Therefore, it is readily apparent that there is a need for a deckless treadmill system that provides the slip-preventative advantages of toothed-belt drive arrangements, yet avoids the complexities inherent in the mechanical and structural design of slip reducing stabilizers. There is a further need for such a deckless treadmill system that effectively provides the requisite support for the opposing peripheral edges of the belt, so as to provide a truly deckless treadmill system and overall stable running platform with improved shock absorption and dispersion characteristics. There is still a further need for such a deckless treadmill system that provides a durable, integrally-formed treadmill belt adapted to provide the requisite structural strength and integrity, and further to effectively absorb and disperse the forceful impact and shock delivered with each repetitively striking foot of the runner.